An enzyme-linked immunosorbent assay (ELISA) for bovine LH capable of monitoring fluctuations in baseline concentrations

Using a Fab'-horseradish peroxidase conjugate, an ELISA for bovine LH was developed and validated. It had good specificity (less than or equal to 0.2% cross-reactivity with FSH or TSH), was not susceptible to interference from plasma components and exhibited very low non-specific binding. It was carried out on microtitre plates and had incubation times totalling 4 or 18 h, not including the initial antibody coating step. The longer incubations gave a lower detection limit (10 pg, 300 amol) and were used when fluctuations in baseline concentrations were being monitored. The values determined were independent of the plasma volume employed, standard added to plasma samples was accurately determined and the results obtained from the analysis of plasma samples correlated closely with those obtained by radioimmunoassay. The assay was applied to the analysis of plasma samples taken from heifers with normal ovarian activity or treated in a number of ways, and in every case the results obtained were similar to those determined by radioimmunoassay and reported in the literature.     

Warming,drought, and disturbances lead to shifts in functional composition: A millennial-scale analysis for Amazonian and Andean sites

Tropical forests are changing in composition and productivity, probably in response to changes in climate and disturbances. The responses to these multiple environmental drivers, and the mechanisms underlying the changes, remain largely unknown. Here, we use a functional trait approach on timescales of 10,000 years to assess how climate and disturbances influence the community-mean adult height, leaf area, seed mass, and wood density for eight lowland and highland forest landscapes. To do so, we combine data of eight fossil pollen records with functional traits and proxies for climate (temperature, precipitation, and El Niño frequency) and disturbances (fire and general disturbances). We found that temperature and disturbances were the most important drivers of changes in functional composition. Increased water availability (high precipitation and low El Niño frequency) generally led to more acquisitive trait composition (large leaves and soft wood). In lowland forests, warmer climates decreased community-mean height probably because of increased water stress, whereas in highland forests warmer climates increased height probably because of upslope migration of taller species. Disturbance increased the abundance of acquisitive, disturbance-adapted taxa with small seeds for quick colonization of disturbed sites, large leaves for light capture, and soft wood to attain fast height growth. Fire had weak effects on lowland forests but led to more stress-adapted taxa that are tall with fast life cycles and small seeds that can quickly colonize burned sites. Site-specific analyses were largely in line with cross-site analyses, except for varying site-level effects of El Niño frequency and fire activity, possibly because regional patterns in El Niño are not a good predictor of local changes, and charcoal abundances do not reflect fire intensity or severity. With future global changes, tropical Amazonian and Andean forests may transition toward shorter, drought- and disturbance-adapted forests in the lowlands but taller forests in the highlands.     

Scent marking and resource defence by male coypus (Myocastor coypus)

The alternative ideas that scent marking functions mainly in intrasexual competition or for attracting or stimulating mates were tested using data from a 16-year study of coypus, Myocastor coypus . Male coypus have a large anal gland, specialized for marking. Despite year-round breeding, the anal gland shows regular seasonal variation with marked enlargement in OctobeDecember. The analysis supported the hypothesis that this seasonal increase in glandular activity was linked to intrasexual competition: the size of the autumn peak was correlated with the increase in male numbers from the previous season and with the frequency of fighting scars. There were no relationships between gland size and any measures of the availability of mates. Increased scent marking may have been part of the response by resource-holding males to male recruits as these competed for existing territories. The timing of the autumn peak in marking and fighting may have been a response to the accumulation of non-resource-holding males over the summer (when recruitment exceeded mortality in the population) and to increasing accessibility within previously dense wetland habitats; together, these factors may cause a switch from scramble to despotic competition and an increase in scent marking to help keep the costs of resource defence within economic limits.     

Facultative variation in the timing of parturition by female coypus (Myocastor coypus), and the cost of delay

Female coypus Myocastor coypus in captivity produce more litters than expected by chance following days when they are undisturbed and less after they are disturbed. The observed distribution can be explained using simulations which assume that females can delay parturition for up to three days, depending on the level of disturbance on a previous day. The advantage of delay for wild coypus may be that parturient females can delay parturition if detected by a predator and move to a safer location. The main cost of delay is an increase in the average proportion of young that die in the last few days of pregnancy and in the days following parturition. These costs and benefits may be similar to those involved in the evolution of gestation periods.     

Creatine Phosphokinase Activity during Lithium Treatment

In a group of patients suffering from manic depressive illness treated with lithium carbonate occasional large increases in creatine phosphokinase (C.P.K.) activity were seen. These were found to occur at times when the patients were stable in mood and clinically well. The serum lithium levels were adequate in all cases at the time of raised C.P.K. activity. Raised C.P.K. activity can be an indication that the disease is active but is controlled by lithium.